The invention relates to a laminated optical component which comprises a supporting member manufactured from a transparent inorganic material and having on at least one side a layer of a radiation-cured lacquer the free surface of which has a defined shape.
Such a component is known from published Netherlands Patent Application No. 81.04.588 in the name of Applicants.
It is the object of the invention to provide a high-grade optical component of great precision the quality of which is maintained at a high level in the course of years and which can be manufactured in a rapid and cheap manner.
Applicants have found that the quality of a laminated optical component depends considerably on the properties of the lacquer used both in the cured and in the non-cured condition. Furthermore, the properties of the lacquer must be accurately matched to those of the material from which the supporting member is manufactured.
According to the recognition underlying the present invention the lacquer must satisfy a package of requirements. For example, in the cured condition the lacquer must readily adhere to the supporting member. A suitable adhesive which copolymerises with the lacquer is notably .gamma.-methacryloyloxypropyltrimethoxysilane. The adhesive bond must be capable of withstanding both temperature fluctuations and moisture for a long period of time. The cured lacquer layer may not be attacked by components in the atmosphere or by components such as Na.sup.+ and K.sup.+ ions which may diffuse to the lacquer layer from the supporting member, for example a glass supporting member. The cured lacquer layer must exhibit no or no noteworthy internal stresses and must have a comparatively high refractive index of n.sub.D =1.56 or higher.
During curing the shrinkage must be small, at most in the order of magnitude of a few percent by volume. Furthermore a good resistance to deformation, hardness and scratch resistance are of importance. In the uncured condition the lacquer must have a viscosity of preferably 2-4 Pa.s at 20.degree. C. and it must cure rapidly. The curing time is at most one minute and is preferably at most 10 to 20 seconds, with an illumination intensity of 2-20 mJ/cm.sup.2 (.lambda.=300-400 nm).
The invention provides a laminated optical component of the type mentioned in the opening paragraph which has a permanent high-grade quality and in which notably the lacquer used satisfies the above-mentioned package of requirements.